Since the development of computer networks, security has been a concern of administrators of computer systems and computer networks. As a result, many different methods of securing computers have been used. A computer system may have one or more facilities that apply security policies for the computer. Further, a computer system may be disposed within a computer network that implements additional security policies that impact the computer system (and possibly other) in the computer network. For example, a computer network may have one or more network computer systems that can be considered to sit above the computer system in a computer network hierarchy, and that must approve and/or relay communications to and from the computer system and possibly other devices in the network.
One security facility that has been used for computer systems and computer networks is a firewall. Firewalls provide security for computer systems by regulating, according to one or more firewall policies, what data is allowed into and out of a single computer or a computer network. Firewalls may be installed in different places on a network. For example, firewalls may be installed on a computer system that is dedicated to implementing the firewall and that is placed at an entry/exit point for the entire network or some portion of it (i.e., the “edge” of the network). Alternatively, firewalls may be installed locally on a single computer system to be protected. Based on certain parameters, data may be allowed to pass through the firewall to its destination or may be blocked by the firewall. These parameters may be based on a variety of data characteristics and are regulated by firewall rules stored by the firewall policy.